187 



of other favourable circumstances, will these bituminous substances 

 be found, in their several approaches to that state to which the laws 

 of nature seem to have particularly destined them. 



Peat, that combustible and inflammable substance, generally 

 found in considerable masses at a little depth beneath the surface 

 of the earth, possessing chemical properties essentially different 

 from every other substance which has not derived its existence from 

 the same origin, appears to be the first product of this kind of fer- 

 mentation, and to have been formed in situations not favourable to 

 the rapid completion of this process. The celerity with which this 

 process is accomplished must depend on the closeness with which 

 the gaseous principles are secured ; but it should be considered, 

 that such peat-bogs, as are comparatively but of modern formation, 

 are covered by a coat of vegetable mould, in an humid state, of no 

 considerable degree of thickness, and therefore the escape of the 

 more volatile principles, and the admission of atmospheric air, is 

 only partially prevented ; the process must therefore be carried on 

 with much less effect than in those cases which will be hereafter 

 mentioned, where vast masses of vegetable matters have been sud- 

 denly buried under a considerable thickness of earthy deposition. 



The abundance of hydrogen, carbon, and oxygen, in peat, is 

 sufficiently demonstrated by its analysis. By the early analysis of 

 Schoockius, we learn that it yields an oil much resembling the oil of 

 amber, with an acid liquor. Mons. Fourcroy relates, that, on expos- 

 ing peat to the action of heat in a distillatory apparatus, a yellow or 

 reddish foetid water is obtained, an oil of a most disagreeable odour, 

 with carbonate of ammonia, and carbonated hydrogen gas, also 

 smelling most disagreeably ; a coal being left which is frequently 

 pyrophoric, and which yields, after incineration, muriate and sul- 

 phate of soda and of pot-ash, mixed with the phosphate and sul-' 

 phate of lime, and with the oxides of iron and of manganese *. 



* Syst. des Connois. Chem. torn. viii. p. 233. 



